Heat transferring device



Feb. 17, 1942. D. TENNEY HEAT TRANSFERRING DEVICE Filed April 6, 1938INVENTOR;

Orv/7hr Tenney a) Mv- W ATTORNEYS tips of all of the radiating fingers.

Patented Feb. 17, 1942 UNITED STATE HEAT TRANSFERRING DEVICE DwightTenney, Verona, N. J., assignor to Edwin F. Tilley, Dunellen, N. J.

Application April 6, 1938, Serial No. 200,357

1 Claim.

This invention relates to heat exchange devices. It is in the nature ofan improvement upon heat exchange devices of the type which consists ofa tube or conduit for carrying a heating or cooling medium and providedwith a heat transferring element which consists of a strip of metalwound spirally about the tube and provided with integral, radiallyextending fingers.

Such a device is subject to the objection that the radially extendingfingers have no substantial strength or rigidity so that they are apt tobe disarranged and deformed during shipment or other handling of thedevice. It is necessary, therefore, that the device be packed andhandled with the utmost care to avoid detrimental deformation. Thedevice is also subject to the objection that the finger edges are raw,sharp edges which are apt to cut or scratch the hands of workmen who arerequired to handle or install the device.

It is an object of the present invention to overcome these diflicultiesof the prior structure and at the same time to increase the heattransferring efiiciency. To these ends, the device is, in general,constructed as before, but there is added a binding strip of sheet metalwhich is spiral in form and which is folded over to embrace the Thebinding strip, though itself light, combines with the radiating fingersto produce a rigid and substantial wound spirally. around the tube I,this strip being formed with a multiplicity of radiating fingers 3 whichare integral with the strip, and which project substantially at rightangles to the strip body and substantially radially of the tube l. Asheet metal binding strip 4 is folded about and pressed upon the outerextremities of all of the fingers 3, the strip 4 taking a helical formas illustrated in conformity with the disposition of the outerextremities of the fingers.

The strip 4, though of light gauge metal, is itself a fairly rigidmember because of the fact that it is folded upon itself. The strip,moreover, serves to combine and unite the outer extremities of all ofthe fingers so that the fingers support the strip and afford mutualsupport to structure which is not at all fragile or delicate and whichcan be handled and shipped, therefore, without liability of beingdamaged. The strip moreover forms a smooth guard edge for the edges offingers which protect the workmans hands against liability of cuts. Thestrip further provides an additional metallic body for promoting thetransference of heat, and thereby increases the heat transferringeiliciency of the structure.

Other objects and advantages of the invention will hereinafter appear.

In the drawing forming part of this specification and illustrating apractical and advantageous embodiment of the invention;

Fig. 1 is a sectional. plan view partly broken away of a deviceembodying the invention;

Fig. 2 is a fragmentary view in side elevation partly broken away of thedevice of Fig. 1; and

Fig. 3 is a sectional, detail view illustrating a A strip of metal 2 isone another through the strip. The result is that the fragility anddelicacy of the radiating fingers is completely eliminated and a sturdyand substantial structure is produced which is not at all likely to bedamaged when handled without special or extraordinary care.

The binding strip 4, moreover, serves to cover and guard the raw edgesof the outer extremities of the fingers 3, thereby substantiallyeliminating all likelihood of a workman cutting or scratching his handsin handling or installing the device. This latter point is of importancein protecting the mechanics who make the device, the persons who packand unpack the device before and after transportation, and the workmenwho install the device for use.

The binding strip 4 has the still further advantage that it provides anadded heat absorbing body of metal, in heat transferring relation withthe fingers 3, which serves to increase the heat transferring capacityof the device.

The device may be made in any suitable manner and of any suitablematerial having high heat conductivity, such as copper or aluminum.

-A method of making the device which is very economical and advantageousinvolves mounting the tube I for rotation and feeding a strip of sheetmetal from a reel toward the rotating tube. On its way to the tube thestrip 2 has slits formed in it to divide a portion of its width intofingers 3, and the fingers are then bent at right angles to theunsevered body of the strip. The strip is wound continuously on to thetube in the form illustrated in Figs. 1 and 2. A strip of metal to formthe binding strip 4 is also fed from a reel toward the revolving tube linto meeting relation with the outer extremities of the fingers 3. Whiletraveling toward such meeting relation, the

strip is first bent to the acute angular form illustrated in dot anddash lines in Fig. 3. In this form' it meets the outer end of eachfinger I in the same radial plane in which the inner end of the fingermeets the tube I. At that point the strip 4 i folded inward to the finalor full line condition illustrated in Fig. 3. The tube holder may bemounted upon a carriage'which is driven in the direction of the axis ofthe tube I, in barmany with the pitch of the spiral or, if preferred,the tube holder may be axially immovable and the feeding and formingmechanisms for the strips 2 and 4 may be mounted upon a carriage whichis driven in the direction of the axis of the tube I in harmony with thepitch of the spiral.

The parts having been assembled in the manner described, the entiredevice is desirably immersed in acid to clean the surface and is driedby heat. It is then held over a solder pot while molten solder is pouredover the entire exterior surface, and is subjected to a blast of air toblow away excess solder. The solder coated device is then quenched. Thistreatment causes the solder to fill in crevices which may remain betweenthe strip 2 and the tube I, between adjacent turns of the strip 2, andbetween the fingers and the strip 4. The thermal conductivity of thedevice is substantially improved by thus improving the metal to metalcontact. and at the same time the structure is made more rigid by fixingthe parts more securely and firmly in relation to one another.

I have described what I believe to be the best embodiments of myinvention. I do not wish. however, to be confined to the embodimentsshown, but what I desire to cover by letters Patent is set forth in theappended claim.

I claim:

A heat transferring device, comprising in combination, a substantiallycylindrical. body. a strip of thin sheet metal wound helically thereonand having a multiplicity of integral radiating fingers with the outerends of the same spaced and separated but disposed in a substantialhelical series and a strip of thin sheet metal extended continuouslyover the separated ends of said radiating fingers and folded flat downover the opposite faces of. said fingers in clamping engagementtherewith and forming a continuous helical guard enclosing and entirelycovering the ends of said fingers and binding the separated fingerstogether in their spaced relation.

DWIGHT TENNEY.

